Preparation of zirconium phosphate activated carbon adsorbent

Abstract

The present invention is directed to a method for preparing a homogenous activated carbon/zirconium or hafnium phosphate product in situ which comprises mixing a carbonaceous organic material with a zirconium or hafnium compound and a phosphoric acid or phosphate salt, and heat-treating said mixture under conditions to convert the carbonaceous material into activated carbon and to convert the zirconium or hafnium compound into zirconium or hafnium phosphate. Advantageously, a molar excess of phosphoric acid over that required to convert the zirconium (or hafnium) compound into zirconium (or hafnium) phosphate is used. Advantageously, also, the heat-treated mixture is washed to remove excess phosphoric acid and dried to remove moisture. Another advantageous embodiment of the invention comprises forming the mixture into a desired shape prior to its heat-treating.

I claim: 
     
       1. A method for preparing a homogenous activated carbon/zirconium phosphate or hafnium phosphate product in situ which comprises: (a) mixing a carbonaceous organic material, a zirconium or hafnium compound, and phosphoric acid or a phosphate salt; and   (b) heat-treating said mixture under conditions to convert said carbonaceous material into activated carbon and to convert said zirconium or hafnium compound into zirconium phosphate or hafnium phosphate.   
     
     
       2. The method of claim 1 wherein a zirconium compound is used in said mixture. 
     
     
       3. The method of claim 1 wherein said zirconium or hafnium compound is a salt of zirconium or hafnium. 
     
     
       4. The method of claim 3 wherein said compound is a halide or oxide of zirconium or hafnium. 
     
     
       5. The method of claim 1 wherein said heat-treating is conducted in air at a temperature of not less than about 350° C. 
     
     
       6. The method of claim 5 wherein said heat-treatment is conducted at a temperature of between about 450° and 550° C. 
     
     
       7. The method of claim 1 wherein said heat-treated mixture is washed with water to remove excess phosphoric acid. 
     
     
       8. The method of claim 7 wherein said washed product is dried to a desired moisture content. 
     
     
       9. The method of claim 1 wherein said mixture is formed into a desired shape prior to said heat-treating. 
     
     
       10. The method of claim 1 wherein phosphoric acid is used in said mixture in a proportion of that required to convert said zirconium or hafnium compound to its corresponding phosphate and an excess ranging from about 0.5 to about 2.5 times the weight of said carbonaceous organic material.